1999 Chevy Suburban

Tiny
BLESSEDONE333
  • MEMBER
  • 1999 CHEVROLET SUBURBAN
  • V8
  • 4WD
  • AUTOMATIC
  • 177,000 MILES
Got a 454 BIG BLOCK 78.4L chevy truck

I've replaced the wires, plugs, cap & rotor, timed to factory, put new injectors, cleaned heads, replaced catalytic converters and MAP sensor and it still runs rough at idle 800 rpm and has very poor acceleration off the line. Once it's up to speed it's okay - like past 35 miles an hour but it's still dogging it after I did all that replacement parts. I have a code reader also and it's not coming up with anything on it that I have not already replaced. Please help
Sunday, March 14th, 2010 AT 4:58 PM

3 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Hi blessedone333, Welcome to 2carpros and Ty for the donation.

Clean out the idle air control valve, also clean the mass airflow sensor with approved cleaner and test the throttle position sensor, also clean out the EGR valve
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Sunday, March 14th, 2010 AT 8:33 PM
Tiny
BLESSEDONE333
  • MEMBER
  • 2 POSTS
We think it might be a faulty camshaft to crankshaft corraltion error

we have a code reading scanner but it's slow going as to why the rough running after replacing all of the items I listed
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Sunday, March 14th, 2010 AT 9:01 PM
Tiny
2 LINSEY
  • MECHANIC
  • 287 POSTS
Thank you for using 2CarPros. Com. We appreciate your donation and look forward to helping you in the future.
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Monday, March 15th, 2010 AT 5:03 PM

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